1. Field of the Invention
The present invention relates to a vehicular air conditioner having a cooling means, a heating means, and an air-mixing door.
2. Description of the Related Art
Vehicular air conditioners installed on vehicles adjust the temperature and humidity in the passenger compartment by mixing air cooled by an evaporator and air heated by a heater core at a desired mixing ratio and delivering the mixed air from a defroster outlet, a face outlet, or a foot outlet into the passenger compartment. For increasing the comfort of occupants or passengers in the passenger compartment, it is necessary to mix the cooled air and the warmed air in as good a state as possible.
FIG. 4 of the accompanying drawings shows in cross section a vehicular air conditioner 2 having a mechanism for mixing cooled air and warmed air at a suitable mixing ratio and supplying the mixed air to the passenger compartment (see Japanese laid-open patent publication No. 11-342721). Air cooled by an evaporator 4 is introduced by an air mixing door 10 into a first passage 12 or a second passage 14. The air introduced into the first passage 12 is heated by a heater core 6 and then introduced by an outlet door 16 into a third passage 18 or a fourth passage 20. The air introduced into the fourth passage 20 is supplied to a face outlet 22. The air introduced into the third passage 18 is supplied by an outlet door 24 to a defroster outlet 26 or a foot outlet 28. Curved guide plates 32 are mounted by stays 30 on a surface of the outlet door 16 which faces the third passage 18.
When the outlet door 16 is positioned as shown in FIG. 4, the air heated into warmed air by the heater core 6 is changed in direction by the guide plates 32 and introduced into the third passage 18. The air supplied as cooled air to the second passage 14 is introduced across the stays 30 into the third passage 18. Since the warmed air and the cooled air that are supplied to the third passage 18 at this time are separated from each other by the guide plates 32, the warmed air supplied from the heater core 6 is introduced into the third passage 18 without being blocked by the cooled air introduced from the second passage 14. Therefore, the warmed air and the cooled air can be mixed with each other in the third passage 18 without staying stagnant and suffering increased resistance, and can be supplied to the defroster outlet 26 or the foot outlet 28.
FIG. 5 of the accompanying drawings shows a vehicular air conditioner 34 (see Japanese laid-open patent publication No. 4-95520). In the vehicular air conditioner 34, air cooled by an evaporator 36 is supplied to a bypass passage 38 and also supplied by an air mixing door 40 to a heater core 42. A bypass door 44 mixes the air introduced into the bypass passage 38 with the air heated by the heater core 42, and the mixed air is supplied by an outlet door 46 or 48 to a face outlet 50 or a foot outlet 52. As shown in FIG. 6 of the accompanying drawings, the bypass door 44 comprises a plurality of juxtaposed parallel sectorial walls 54 which are joined by successive partitions 56 that are alternately positioned on opposite sides of the walls 54.
The warmed air introduced from the heater core 42 and the cooled air introduced from the bypass passage 38 are changed in direction by the partitions 56 and supplied to the face outlet 50 or the foot outlet 52. Since the warmed air and the cooled air flowing along the bypass door 44 are divided into laminar flows by the walls 54, they can be mixed into a uniform stream of air.
With the vehicular air conditioner 2 shown in FIG. 4, the guide plates 32 mounted on the outlet door 16 separate the warmed air supplied from the heater core 6 and the cooled air supplied from the second passage 14, allowing the warmed air to be introduced at a desired rate into the third passage 18 without being blocked by the cooled air. For mixing the warmed air and the cooled air appropriately with each other, it is necessary that the distance from the third passage 18 to the defroster outlet 26 or the foot outlet 28 be increased. As a result, the vehicular air conditioner 2 is relatively large in size.
Furthermore, since the warmed air and the cooled air are separated from each other by the guide plates 32, when a foot/defroster mode for ejecting air from both the defroster outlet 26 and the foot outlet 28 is selected, the temperature of the air ejected from the defroster outlet 26 and the temperature of the air ejected from the foot outlet 28 are largely different from each other, tending to make the passengers feel uncomfortable.
As the guide plates 32 are mounted only on the side of the outlet door 16 which faces the third passage 18, when a bi-level mode for ejecting air from both the face outlet 22 and the foot outlet 28 is selected, the temperature of the air ejected from the face outlet 22 and the temperature of the air ejected from the foot outlet 28 are also largely different from each other.
With the vehicular air conditioner 34 shown in FIGS. 5 and 6, when air is ejected from either the face outlet 50 or the foot outlet 52, since the warmed air and the cooled air are appropriately mixed with each other by the bypass door 44, the mixed air with little temperature differences is ejected. However, when a bi-level mode for ejecting air from both the face outlet 50 and the foot outlet 52 is selected, the bypass door 40 presents itself as an obstacle, increasing the temperature difference between the air ejected from the face outlet 50 and the air ejected from the foot outlet 52.